Determination by light scattering

This result uses the already established fact that M = when the molecular weight is determined by light scattering for a polydisperse system. 

The molecular weights of PAs are often not very high (M > 20,000) in this range M can be determined by endgroup analysis or, less frequently, by osmometry, Mw can be determined by light scattering. Both M and Mw can indirectly be determined by HPLC. 

Theta temperature is one of the most important thermodynamic parameters of polymer solutions. At theta temperature, the long-range interactions vanish, segmental interactions become more effective and the polymer chains assume their unperturbed dimensions. It can be determined by light scattering and osmotic pressure measurements. These techniques are based on the fact that the second virial coefficient, A2, becomes zero at the theta conditions. 

Turbidity as determined by light-scattering measurements, and the same quantity corrected for dissymmetry (Chap. VII). 

Debye, P. (1947) Molecular-weight determination by light scattering./. Phys. Colloid Chem. 51, 18-32. 

Particle size of the micelle was determined by light scattering. Distance between the copper electrodes was maintained at 1 cm. After electrochemical deposition the electrode was removed from the cell and dried at 100° C for 10 min to remove water. Electrochemical deposition was done initially under galvanostatic conditions with the applied current density of 30 - 60 A per square foot, and then changed to potentiostatic conditions after achieving a required film thickness. 

Table 15.1 Comparison of the Sizes and Shapes of Polyaphrons as Determined by Electron Microscopy (Cryo-TEM) with Those of Dispersed CLAs as Determined by Light Scattering... 

Determined by GPC Determined by light scattering method dppf=l,l -Diphenylphosphinoferrocene. 

Intrinsic Viscosity. Due to the complicating effects of aggregation and selective adsorption on the A2 values determined by light scattering, another means was sought to characterize the quality of solvents for PVB. The alternate means chosen was intrinsic viscosity measurements. Theory relates the intrinsic viscosity to the polymer chain dimensions through the expression (24)... 

Bulk properties associated with large deformations, such as viscosity and toughness, are most closely associated with M . The values of are most often determined by light-scattering photometry. 

McKellar, B. H. J., 1976. What property of a haze is determined by light scattering 2. Nonuniform particles of arbitrary shape, Appl. Opt., 15, 2464-2467. 

It is important to note that the values of the second virial coefficients determined by light scattering are weight-average quantities. The general expression for the second virial coefficient of a polydisperse polymer is as follows (Casassa, 1962) ... 

Ruis, H.G.M., Venema, P., van der Linden, E. (2007). Relation between pH-induced stickiness and gelation behaviour of sodium caseinate aggregates as determined by light scattering and rheology. FoodHydrocolloids, 21, 545-554. 

Figure 7.22 Microstructure of acidified mixed emulsions (20 vol% oil, 0.5 wt% sodium caseinate) containing different concentrations of dextran sulfate (DS). Samples were prepared at pH = 6 in 20 mM imidazole buffer and acidified to pH = 2 by addition of HCl. Emulsions were diluted 1 10 in 20 mM imidazole buffer before visualization by differential interference contrast microscopy (A) no added DS (B) 0.1 wt% DS (C) 0.5 wt% DS (D) 1 wt% DS. Particle-size distributions of the diluted emulsions determined by light-scattering (Mastersizer) are superimposed on the micrographs, with horizontal axial labels indicating the particle diameter (in pm). Reproduced with permission from Jourdain et al. (2008).

The Mg-Al-C03-LDH used as adsorbent and sorbent was prepared with an Mg Al ratio of 2 1 by the coprecipitation method at variable pH [6], The material obtained was characterised by powder X-ray diffraction (PXRD, using a Siemens D-5005 X-ray diffractometer), and elemental and thermal analyses. The material showed the characteristic lamellar structure with a basal spacing of 7.6 A, specific surface area of 87.1 m2 g 1, determined by the N2-BET adsorption isotherm, and an approximate minimum molecular formula [Mg, MAt, (oh) m ](CO, ) 5 2.3 i(h2o) The size distribution and the average size of the LDH particles were determined by light scattering, using a Zetasizer 4 from Malvern. 

Polyacetylene may also be produced from a soluble precursor polymer by the Durham route, described earlier. In- this case the soluble precursor can be studied by conventional solution methods, provided that it is kept cold enough to prevent transformation. The molecular weight of the precursor has been determined by light scattering and low-temperature GPC 326) and corresponds to a polyacetylene chain with a molecular weight of about 200,000, with Mw/Mn of about 2. 

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